It is a moving experience for me to be back again in the university and to be able once again to give a lecture at this podium. I think back to those years when, after a pleasant period at the Freisinger Hochschule, I began teaching at the University of Bonn. That was in 1959, in the days of the old university made up of ordinary professors. The various chairs had neither assistants nor secretaries, but in recompense there was much direct contact with students and in particular among the professors themselves. We would meet before and after lessons in the rooms of the teaching staff. There was a lively exchange with historians, philosophers, philologists and, naturally, between the two theological faculties. Once a semester there was a dies academicus, when professors from every faculty appeared before the students of the entire university, making possible a genuine experience of universitas – something that you too, Magnificent Rector, just mentioned – the experience, in other words, of the fact that despite our specializations which at times make it difficult to communicate with each other, we made up a whole, working in everything on the basis of a single rationality with its various aspects and sharing responsibility for the right use of reason – this reality became a lived experience. The university was also very proud of its two theological faculties. It was clear that, by inquiring about the reasonableness of faith, they too carried out a work which is necessarily part of the “whole” of the universitas scientiarum, even if not everyone could share the faith which theologians seek to correlate with reason as a whole. This profound sense of coherence within the universe of reason was not troubled, even when it was once reported that a colleague had said there was something odd about our university: it had two faculties devoted to something that did not exist: God. That even in the face of such radical scepticism it is still necessary and reasonable to raise the question of God through the use of reason, and to do so in the context of the tradition of the Christian faith: this, within the university as a whole, was accepted without question.
I was reminded of all this recently, when I read the edition by Professor Theodore Khoury (Münster) of part of the dialogue carried on – perhaps in 1391 in the winter barracks near Ankara – by the erudite Byzantine emperor Manuel II Paleologus and an educated Persian on the subject of Christianity and Islam, and the truth of both. It was presumably the emperor himself who set down this dialogue, during the siege of Constantinople between 1394 and 1402; and this would explain why his arguments are given in greater detail than those of his Persian interlocutor. The dialogue ranges widely over the structures of faith contained in the Bible and in the Qur’an, and deals especially with the image of God and of man, while necessarily returning repeatedly to the relationship between – as they were called – three “Laws” or “rules of life”: the Old Testament, the New Testament and the Qur’an. It is not my intention to discuss this question in the present lecture; here I would like to discuss only one point – itself rather marginal to the dialogue as a whole – which, in the context of the issue of “faith and reason”, I found interesting and which can serve as the starting-point for my reflections on this issue.
In the seventh conversation (διάλεξις – controversy) edited by Professor Khoury, the emperor touches on the theme of the holy war. The emperor must have known that surah 2, 256 reads: “There is no compulsion in religion”. According to some of the experts, this is probably one of the suras of the early period, when Mohammed was still powerless and under threat. But naturally the emperor also knew the instructions, developed later and recorded in the Qur’an, concerning holy war. Without descending to details, such as the difference in treatment accorded to those who have the “Book” and the “infidels”, he addresses his interlocutor with a startling brusqueness, a brusqueness that we find unacceptable, on the central question about the relationship between religion and violence in general, saying: “Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached.” The emperor, after having expressed himself so forcefully, goes on to explain in detail the reasons why spreading the faith through violence is something unreasonable. Violence is incompatible with the nature of God and the nature of the soul. “God”, he says, “is not pleased by blood – and not acting reasonably (σὺν λόγω) is contrary to God’s nature. Faith is born of the soul, not the body. Whoever would lead someone to faith needs the ability to speak well and to reason properly, without violence and threats… To convince a reasonable soul, one does not need a strong arm, or weapons of any kind, or any other means of threatening a person with death…”.
The decisive statement in this argument against violent conversion is this: not to act in accordance with reason is contrary to God’s nature. The editor, Theodore Khoury, observes: For the emperor, as a Byzantine shaped by Greek philosophy, this statement is self-evident. But for Muslim teaching, God is absolutely transcendent. His will is not bound up with any of our categories, even that of rationality. Here Khoury quotes a work of the noted French Islamist R. Arnaldez, who points out that Ibn Hazm went so far as to state that God is not bound even by his own word, and that nothing would oblige him to reveal the truth to us. Were it God’s will, we would even have to practise idolatry.
At this point, as far as understanding of God and thus the concrete practice of religion is concerned, we are faced with an unavoidable dilemma. Is the conviction that acting unreasonably contradicts God’s nature merely a Greek idea, or is it always and intrinsically true? I believe that here we can see the profound harmony between what is Greek in the best sense of the word and the biblical understanding of faith in God. Modifying the first verse of the Book of Genesis, the first verse of the whole Bible, John began the prologue of his Gospel with the words: “In the beginning was the λόγος”. This is the very word used by the emperor: God acts, σὺν λόγω, with logos. Logos means both reason and word – a reason which is creative and capable of self-communication, precisely as reason. John thus spoke the final word on the biblical concept of God, and in this word all the often toilsome and tortuous threads of biblical faith find their culmination and synthesis. In the beginning was the logos, and the logos is God, says the Evangelist. The encounter between the Biblical message and Greek thought did not happen by chance. The vision of Saint Paul, who saw the roads to Asia barred and in a dream saw a Macedonian man plead with him: “Come over to Macedonia and help us!” (cf. Acts 16:6-10) – this vision can be interpreted as a “distillation” of the intrinsic necessity of a rapprochement between Biblical faith and Greek inquiry.
In point of fact, this rapprochement had been going on for some time. The mysterious name of God, revealed from the burning bush, a name which separates this God from all other divinities with their many names and simply asserts being, “I am”, already presents a challenge to the notion of myth, to which Socrates’ attempt to vanquish and transcend myth stands in close analogy.Within the Old Testament, the process which started at the burning bush came to new maturity at the time of the Exile, when the God of Israel, an Israel now deprived of its land and worship, was proclaimed as the God of heaven and earth and described in a simple formula which echoes the words uttered at the burning bush: “I am”. This new understanding of God is accompanied by a kind of enlightenment, which finds stark expression in the mockery of gods who are merely the work of human hands (cf. Ps 115). Thus, despite the bitter conflict with those Hellenistic rulers who sought to accommodate it forcibly to the customs and idolatrous cult of the Greeks, biblical faith, in the Hellenistic period, encountered the best of Greek thought at a deep level, resulting in a mutual enrichment evident especially in the later wisdom literature. Today we know that the Greek translation of the Old Testament produced at Alexandria – the Septuagint – is more than a simple (and in that sense really less than satisfactory) translation of the Hebrew text: it is an independent textual witness and a distinct and important step in the history of revelation, one which brought about this encounter in a way that was decisive for the birth and spread of Christianity. A profound encounter of faith and reason is taking place here, an encounter between genuine enlightenment and religion. From the very heart of Christian faith and, at the same time, the heart of Greek thought now joined to faith, Manuel II was able to say: Not to act “with logos” is contrary to God’s nature.
In all honesty, one must observe that in the late Middle Ages we find trends in theology which would sunder this synthesis between the Greek spirit and the Christian spirit. In contrast with the so-called intellectualism of Augustine and Thomas, there arose with Duns Scotus a voluntarism which, in its later developments, led to the claim that we can only know God’s voluntas ordinata. Beyond this is the realm of God’s freedom, in virtue of which he could have done the opposite of everything he has actually done. This gives rise to positions which clearly approach those of Ibn Hazm and might even lead to the image of a capricious God, who is not even bound to truth and goodness. God’s transcendence and otherness are so exalted that our reason, our sense of the true and good, are no longer an authentic mirror of God, whose deepest possibilities remain eternally unattainable and hidden behind his actual decisions. As opposed to this, the faith of the Church has always insisted that between God and us, between his eternal Creator Spirit and our created reason there exists a real analogy, in which – as the Fourth Lateran Council in 1215 stated – unlikeness remains infinitely greater than likeness, yet not to the point of abolishing analogy and its language. God does not become more divine when we push him away from us in a sheer, impenetrable voluntarism; rather, the truly divine God is the God who has revealed himself as logos and, as logos, has acted and continues to act lovingly on our behalf. Certainly, love, as Saint Paul says, “transcends” knowledge and is thereby capable of perceiving more than thought alone (cf. Eph 3:19); nonetheless it continues to be love of the God who is Logos. Consequently, Christian worship is, again to quote Paul – “λογικη λατρεία”, worship in harmony with the eternal Word and with our reason (cf. Rom 12:1).
This inner rapprochement between Biblical faith and Greek philosophical inquiry was an event of decisive importance not only from the standpoint of the history of religions, but also from that of world history – it is an event which concerns us even today. Given this convergence, it is not surprising that Christianity, despite its origins and some significant developments in the East, finally took on its historically decisive character in Europe. We can also express this the other way around: this convergence, with the subsequent addition of the Roman heritage, created Europe and remains the foundation of what can rightly be called Europe.
The thesis that the critically purified Greek heritage forms an integral part of Christian faith has been countered by the call for a dehellenization of Christianity – a call which has more and more dominated theological discussions since the beginning of the modern age. Viewed more closely, three stages can be observed in the programme of dehellenization: although interconnected, they are clearly distinct from one another in their motivations and objectives.
Dehellenization first emerges in connection with the postulates of the Reformation in the sixteenth century. Looking at the tradition of scholastic theology, the Reformers thought they were confronted with a faith system totally conditioned by philosophy, that is to say an articulation of the faith based on an alien system of thought. As a result, faith no longer appeared as a living historical Word but as one element of an overarching philosophical system. The principle of sola scriptura, on the other hand, sought faith in its pure, primordial form, as originally found in the biblical Word. Metaphysics appeared as a premise derived from another source, from which faith had to be liberated in order to become once more fully itself. When Kant stated that he needed to set thinking aside in order to make room for faith, he carried this programme forward with a radicalism that the Reformers could never have foreseen. He thus anchored faith exclusively in practical reason, denying it access to reality as a whole.
The liberal theology of the nineteenth and twentieth centuries ushered in a second stage in the process of dehellenization, with Adolf von Harnack as its outstanding representative. When I was a student, and in the early years of my teaching, this programme was highly influential in Catholic theology too. It took as its point of departure Pascal’s distinction between the God of the philosophers and the God of Abraham, Isaac and Jacob. In my inaugural lecture at Bonn in 1959, I tried to address the issue,and I do not intend to repeat here what I said on that occasion, but I would like to describe at least briefly what was new about this second stage of dehellenization. Harnack’s central idea was to return simply to the man Jesus and to his simple message, underneath the accretions of theology and indeed of hellenization: this simple message was seen as the culmination of the religious development of humanity. Jesus was said to have put an end to worship in favour of morality. In the end he was presented as the father of a humanitarian moral message. Fundamentally, Harnack’s goal was to bring Christianity back into harmony with modern reason, liberating it, that is to say, from seemingly philosophical and theological elements, such as faith in Christ’s divinity and the triune God. In this sense, historical-critical exegesis of the New Testament, as he saw it, restored to theology its place within the university: theology, for Harnack, is something essentially historical and therefore strictly scientific. What it is able to say critically about Jesus is, so to speak, an expression of practical reason and consequently it can take its rightful place within the university. Behind this thinking lies the modern self-limitation of reason, classically expressed in Kant’s “Critiques”, but in the meantime further radicalized by the impact of the natural sciences. This modern concept of reason is based, to put it briefly, on a synthesis between Platonism (Cartesianism) and empiricism, a synthesis confirmed by the success of technology. On the one hand it presupposes the mathematical structure of matter, its intrinsic rationality, which makes it possible to understand how matter works and use it efficiently: this basic premise is, so to speak, the Platonic element in the modern understanding of nature. On the other hand, there is nature’s capacity to be exploited for our purposes, and here only the possibility of verification or falsification through experimentation can yield decisive certainty. The weight between the two poles can, depending on the circumstances, shift from one side to the other. As strongly positivistic a thinker as J. Monod has declared himself a convinced Platonist/Cartesian.
This gives rise to two principles which are crucial for the issue we have raised. First, only the kind of certainty resulting from the interplay of mathematical and empirical elements can be considered scientific. Anything that would claim to be science must be measured against this criterion. Hence the human sciences, such as history, psychology, sociology and philosophy, attempt to conform themselves to this canon of scientificity. A second point, which is important for our reflections, is that by its very nature this method excludes the question of God, making it appear an unscientific or pre-scientific question. Consequently, we are faced with a reduction of the radius of science and reason, one which needs to be questioned.
I will return to this problem later. In the meantime, it must be observed that from this standpoint any attempt to maintain theology’s claim to be “scientific” would end up reducing Christianity to a mere fragment of its former self. But we must say more: if science as a whole is this and this alone, then it is man himself who ends up being reduced, for the specifically human questions about our origin and destiny, the questions raised by religion and ethics, then have no place within the purview of collective reason as defined by “science”, so understood, and must thus be relegated to the realm of the subjective. The subject then decides, on the basis of his experiences, what he considers tenable in matters of religion, and the subjective “conscience” becomes the sole arbiter of what is ethical. In this way, though, ethics and religion lose their power to create a community and become a completely personal matter. This is a dangerous state of affairs for humanity, as we see from the disturbing pathologies of religion and reason which necessarily erupt when reason is so reduced that questions of religion and ethics no longer concern it. Attempts to construct an ethic from the rules of evolution or from psychology and sociology, end up being simply inadequate.
Before I draw the conclusions to which all this has been leading, I must briefly refer to the third stage of dehellenization, which is now in progress. In the light of our experience with cultural pluralism, it is often said nowadays that the synthesis with Hellenism achieved in the early Church was an initial inculturation which ought not to be binding on other cultures. The latter are said to have the right to return to the simple message of the New Testament prior to that inculturation, in order to inculturate it anew in their own particular milieux. This thesis is not simply false, but it is coarse and lacking in precision. The New Testament was written in Greek and bears the imprint of the Greek spirit, which had already come to maturity as the Old Testament developed. True, there are elements in the evolution of the early Church which do not have to be integrated into all cultures. Nonetheless, the fundamental decisions made about the relationship between faith and the use of human reason are part of the faith itself; they are developments consonant with the nature of faith itself.
And so I come to my conclusion. This attempt, painted with broad strokes, at a critique of modern reason from within has nothing to do with putting the clock back to the time before the Enlightenment and rejecting the insights of the modern age. The positive aspects of modernity are to be acknowledged unreservedly: we are all grateful for the marvellous possibilities that it has opened up for mankind and for the progress in humanity that has been granted to us. The scientific ethos, moreover, is – as you yourself mentioned, Magnificent Rector – the will to be obedient to the truth, and, as such, it embodies an attitude which belongs to the essential decisions of the Christian spirit. The intention here is not one of retrenchment or negative criticism, but of broadening our concept of reason and its application. While we rejoice in the new possibilities open to humanity, we also see the dangers arising from these possibilities and we must ask ourselves how we can overcome them. We will succeed in doing so only if reason and faith come together in a new way, if we overcome the self-imposed limitation of reason to the empirically falsifiable, and if we once more disclose its vast horizons. In this sense theology rightly belongs in the university and within the wide-ranging dialogue of sciences, not merely as a historical discipline and one of the human sciences, but precisely as theology, as inquiry into the rationality of faith.
Only thus do we become capable of that genuine dialogue of cultures and religions so urgently needed today. In the Western world it is widely held that only positivistic reason and the forms of philosophy based on it are universally valid. Yet the world’s profoundly religious cultures see this exclusion of the divine from the universality of reason as an attack on their most profound convictions. A reason which is deaf to the divine and which relegates religion into the realm of subcultures is incapable of entering into the dialogue of cultures. At the same time, as I have attempted to show, modern scientific reason with its intrinsically Platonic element bears within itself a question which points beyond itself and beyond the possibilities of its methodology. Modern scientific reason quite simply has to accept the rational structure of matter and the correspondence between our spirit and the prevailing rational structures of nature as a given, on which its methodology has to be based. Yet the question why this has to be so is a real question, and one which has to be remanded by the natural sciences to other modes and planes of thought – to philosophy and theology. For philosophy and, albeit in a different way, for theology, listening to the great experiences and insights of the religious traditions of humanity, and those of the Christian faith in particular, is a source of knowledge, and to ignore it would be an unacceptable restriction of our listening and responding. Here I am reminded of something Socrates said to Phaedo. In their earlier conversations, many false philosophical opinions had been raised, and so Socrates says: “It would be easily understandable if someone became so annoyed at all these false notions that for the rest of his life he despised and mocked all talk about being – but in this way he would be deprived of the truth of existence and would suffer a great loss”. The West has long been endangered by this aversion to the questions which underlie its rationality, and can only suffer great harm thereby. The courage to engage the whole breadth of reason, and not the denial of its grandeur – this is the programme with which a theology grounded in Biblical faith enters into the debates of our time. “Not to act reasonably, not to act with logos, is contrary to the nature of God”, said Manuel II, according to his Christian understanding of God, in response to his Persian interlocutor. It is to this great logos, to this breadth of reason, that we invite our partners in the dialogue of cultures. To rediscover it constantly is the great task of the university.
12 September 2006
 Of the total number of 26 conversations (διάλεξις – Khoury translates this as “controversy”) in the dialogue (“Entretien”), T. Khoury published the 7th “controversy” with footnotes and an extensive introduction on the origin of the text, on the manuscript tradition and on the structure of the dialogue, together with brief summaries of the “controversies” not included in the edition; the Greek text is accompanied by a French translation: “Manuel II Paléologue, Entretiens avec un Musulman. 7e Controverse”, Sources Chrétiennes n. 115, Paris 1966. In the meantime, Karl Förstel published in Corpus Islamico-Christianum (Series Graeca ed. A. T. Khoury and R. Glei) an edition of the text in Greek and German with commentary: “Manuel II. Palaiologus, Dialoge mit einem Muslim”, 3 vols., Würzburg-Altenberge 1993-1996. As early as 1966, E. Trapp had published the Greek text with an introduction as vol. II of Wiener byzantinische Studien. I shall be quoting from Khoury’s edition.
 On the origin and redaction of the dialogue, cf. Khoury, pp. 22-29; extensive comments in this regard can also be found in the editions of Förstel and Trapp.
 Controversy VII, 2 c: Khoury, pp. 142-143; Förstel, vol. I, VII. Dialog 1.5, pp. 240-241. In the Muslim world, this quotation has unfortunately been taken as an expression of my personal position, thus arousing understandable indignation. I hope that the reader of my text can see immediately that this sentence does not express my personal view of the Qur’an, for which I have the respect due to the holy book of a great religion. In quoting the text of the Emperor Manuel II, I intended solely to draw out the essential relationship between faith and reason. On this point I am in agreement with Manuel II, but without endorsing his polemic.
 Controversy VII, 3 b–c: Khoury, pp. 144-145; Förstel vol. I, VII. Dialog 1.6, pp. 240-243.
 It was purely for the sake of this statement that I quoted the dialogue between Manuel and his Persian interlocutor. In this statement the theme of my subsequent reflections emerges.
 Cf. Khoury, p. 144, n. 1.
 R. Arnaldez, Grammaire et théologie chez Ibn Hazm de Cordoue, Paris 1956, p. 13; cf. Khoury, p. 144. The fact that comparable positions exist in the theology of the late Middle Ages will appear later in my discourse.
 Regarding the widely discussed interpretation of the episode of the burning bush, I refer to my book Introduction to Christianity,London 1969, pp. 77-93 (originally published in German as Einführung in das Christentum, Munich 1968; N.B. the pages quoted refer to the entire chapter entitled “The Biblical Belief in God”). I think that my statements in that book, despite later developments in the discussion, remain valid today.
 Cf. A. Schenker, “L’Écriture sainte subsiste en plusieurs formes canoniques simultanées”, in L’Interpretazione della Bibbia nella Chiesa. Atti del Simposio promosso dalla Congregazione per la Dottrina della Fede, Vatican City 2001, pp. 178-186.
 On this matter I expressed myself in greater detail in my book The Spirit of the Liturgy, San Francisco 2000, pp. 44-50.
 Of the vast literature on the theme of dehellenization, I would like to mention above all: A. Grillmeier, “Hellenisierung-Judaisierung des Christentums als Deuteprinzipien der Geschichte des kirchlichen Dogmas”, in idem, Mit ihm und in ihm. Christologische Forschungen und Perspektiven, Freiburg 1975, pp. 423-488.
 Newly published with commentary by Heino Sonnemans (ed.): Joseph Ratzinger-Benedikt XVI, Der Gott des Glaubens und der Gott der Philosophen. Ein Beitrag zum Problem der theologia naturalis, Johannes-Verlag Leutesdorf, 2nd revised edition, 2005.
 Cf. 90 c-d. For this text, cf. also R. Guardini, Der Tod des Sokrates, 5th edition, Mainz-Paderborn 1987, pp. 218-221.